Recently, I managed to appeal successfully for WordAds to be run on my other site https://chinesetuition88.com/. Previously, it was rejected a few years ago in 2016 due to insufficient traffic.
For the appeal to be successful, I think that there needs to be at least a significant upwards trend in your traffic. Personally, I had a 500% increase in traffic over 3 years.
If your appeal is successful, a mail will be sent (for me it was within the same day):
Happy to help you. I’ve checked your site stats and it seems that you were on track to be approved next week, so I just put that through for you today instead. You can now finish setting up WordAds via https://wordpress.com/earn/ads-settings/ or the new “WordAds” section under your blog at https://wordpress.com/
I hope that helped. Come back if you have questions. We are happy to help you anytime 🙂
Good luck for anyone trying to apply for WordAds!